Epoxy Resin Volume & Deep Pour Calculator
Calculate total liquid epoxy volume (gallons, ounces, liters) and Part A/B mixing ratios for river tables and void fills. This volume engine computes casting requirements for irregular live-edge slabs and rectangular channels, factoring in mold seepage allowances and wood porosity to eliminate short pours.
How Much Epoxy Do You Need for a River Table?
To calculate total epoxy gallons, multiply the length, average width, and depth of the river cavity in inches, divide by 231 cubic inches per US gallon, and add a 10% safety margin for wood grain absorption: Total Gallons = [(Length × Width × Depth) ÷ 231] × 1.10. For a standard 72″ long by 10″ wide by 1.75″ deep river table, the void measures 1,260 cubic inches (5.45 net gallons), requiring exactly 6.00 gallons (768 fl oz) of mixed epoxy (4.0 gallons Part A and 2.0 gallons Part B for a 2:1 formula).
Epoxy Resin River Table Volume Calculator
Calculate liquid epoxy volume, Part A/B mixing ratios, and pour depths for river tables and slab voids.
How to Pour Deep River Tables Without Thermal Cracking
Follow these four essential resin shop steps to seal live edges, avoid short pours, and control exothermic heat buildup:
Apply a Thin Seal Coat to Raw Live Edges First
Never pour a deep river against raw, unsealed wood. Dry slab fibers release thousands of tiny air bubbles into the liquid resin as it cures. Brush a thin coat of quick-curing tabletop epoxy along the live edges 4 to 6 hours before the primary pour to lock air inside the grain.
Measure and Mix Using the Two-Bucket Method
Pour calculated amounts of Part A and Part B into a clean mixing pail. Stir slowly with a paddle mixer at low speed (under 300 RPM) for 5 full minutes. Pour the mixture into a second clean bucket and stir for another 2 minutes to prevent unmixed resin from curing gummy.
Pour the Resin and Degas Surface Bubbles
Pour the mixed deep-cast epoxy into the center of the mold cavity in a steady stream. Deep-pour epoxies have water-thin viscosity that allows bubbles to rise naturally. Pass a heat gun or propane torch 6 inches above the surface 15 minutes after pouring to pop surface tension bubbles.
Maintain Workshop Ambient Temperature at 68°F to 72°F
Deep-pour epoxy cures slowly over 48 to 72 hours. Keep the shop between 68°F and 72°F (20°C–22°C) with continuous low airflow. Temperatures above 75°F accelerate the exothermic reaction, which can cause large pours to boil, yellow, or crack.
Why Deep Pour Resins Differ Chemically from Tabletop Epoxies
Epoxy polymerization is an exothermic reaction: as epoxide rings cross-link with polyamine hardeners, they release chemical heat. The greater the mass and thickness of the liquid epoxy, the faster heat builds up, which can create a runaway reaction if the wrong resin formulation is used.
Tabletop Resins (1:1 Ratio)
Formulated with highly reactive hardeners that cure hard in 12 to 16 hours. They must never be poured thicker than 1/8″ to 1/4″ per coat. If poured 2″ deep, the resin will boil, turn yellow, release smoke, and fracture into jagged shards.
Deep Casting Resins (2:1 Ratio)
Engineered with slow-reacting aliphatic amines that extend gel time to 24–36 hours. This slow cure releases heat gradually, allowing thick pours up to 2″ or 3″ in a single stage without thermal stress or bubbles.
Curing Volume Shrinkage
Thermoset epoxies shrink between 1.5% and 2.5% by volume as molecules cross-link into a solid lattice. Overfilling the river mold by 1/16″ leaves sufficient material to surface-plane the cured table completely flat.